1. Field of the Invention
The present invention relates to a dust-proof structure, and more particularly, to a dust-proof structure provided on a case of a handheld electronic device for preventing a card connector in the electronic device from being contaminated by dust.
2. Description of Related Art
The multi-media technology has ushered into a new era. A lot of handheld electronic devices like digital camera, PDA, and mobile phone, have been developed, which are required to embody the multi-media technology and thus need a card connector to connect with a memory card, a game card or an extension card. The card is simply inserted into a case of the device through a slot in the case to connect with the card connector. The device usually does not have means on the case for preventing dust from entering into the device through the slot. When dust enters into the device through the slot, it will accumulate on the connector and contaminate contacts of the connector. The contamination of the contacts adversely affects a normal connection between the connector and the inserted card, and accordingly, a normal operation of the handheld electronic device.
FIG. 1 is a schematic perspective, exploded view of a handheld electronic device and a memory card 102, according to the prior art. Referring to FIG. 1, the handheld electronic device has a case 108 defining a slot 108a therethrough, a printed circuit board 106 and a card connector 104 mounted on the printed circuit board 106. The card connector 104 and the printed circuit board 106 are accommodated in the case 108. The slot 108a is aligned with the card connector 104 so that when the memory card 102 is inserted into the case 108 through the slot 108a, the memory card 102 can electrically connect with the card connector 104. However, the handheld electronic device lacks a means, which can prevent dust from entering an inside of the device through the slot 108a. The dust entering the inside of the device may accumulate on and contaminate the card connector 104 and the circuit board 106.
In order to prevent dust from contaminating an electrical connector, U.S. Pat. No. 4,795,354 discloses a dust-proof structure attached to an electrical connector. The dust-proof structure is constructed from two flexible layers and a rigid layer, wherein the two flexible layers are laminated on the rigid layer. The outer one of the flexible layers can be a woven monofilament synthetic fiber, such as nylon. The inner one of the flexible layers can be non-woven and rubber-like, such as natural rubber, silicon rubber, neoprene and so on. The rigid layer is, for example, plastic. However, due to structural limitation, the dust-proof structure of the prior art cannot be not be easily attached to the card connector of the handheld electronic device to prevent the contamination thereof.
U.S. Pat. No. 6,377,451 and U.S. Pat. No. 5,701,216 each discloses a dust-proof structure comprising two panels capable of rotating about two respective shafts. The two panels are urged by springs to close an insertion port thereby to prevent dust from entering an inside of an electronic device. However, the dust-proof structures are mechanisms with a complex setup, numerous parts, a larger size and requires a high production cost.